1. Field of the Invention
The present invention relates generally to therapeutic beds and mattress systems and methods for maintaining their function. The present invention relates more specifically to improved systems and methods for controlling the configuration and characteristics of an inflatable air mattress utilizing an array of networked sensors and control modules.
2. Description of the Related Art
A number of problems are associated with inflatable air mattresses used in medical settings. Some such air mattresses are designed for therapeutic use and include high and low air loss fabric enclosures as well as control systems that alter the air pressure within the mattress in order to help reduce the occurrence of bed sores and similar detrimental effects of a long term bedridden condition. While in general air mattresses must be sufficiently firm to support a patient, they must also be sufficiently soft and resilient so as to be comfortable for the patient. Likewise, when therapeutic variations in the pressure within the air mattress are implemented, it is often difficult to maintain the elevation of the patient off a mattress base over the entire surface of the mattress. If, for whatever reason, the patient makes contact through the mattress surface with the more rigid mattress base, the result is the undesirable and uncomfortable occurrence that is referred to as “bottoming”.
Control systems designed to maintain the inflation of therapeutic mattresses and the like must take into account significant variations in the force that a patient may exert on any single point in the mattress surface in addition to the overall force exerted by the weight of the patient across the mattress surface as an average. Point forces are generally experienced when a patient enters or exits the bed and directs their hands or feet, elbows or knees, into the mattress at a single localized point. In general, control systems that rely strictly on measurements of the pressure within an inflatable mattress fail to prevent the “bottoming” of the patient under a number of situations.
Some efforts to address the maintenance of mattress configuration involve the use of an increasing number of individual inflatable cells; any one of which may experience a large localized force, but with adjoining cells that would support the patient and prevent the “bottoming” from occurring. The problem with mattresses that utilize increased numbers of individual cells is that each cell must be individually connected to the inflation system and individually monitored by whatever control electronics might be put in place. Such mattresses would typically have extensive and quite complex air and electrical conduits running down and through the length of the mattress that individually address each of the inflation and control systems associated with the inflatable platform. The size, expense, complexity, and maintenance of such systems all become significant.
U.S. Pat. No. 6,560,804 issued to Wise et al. entitled System and Methods for Mattress Control in Relation to Patient Distance (Assignee KCI Licensing, Inc.) describes a system and method for detecting and monitoring the distance between a patient and a reference point on an inflatable air mattress and for controlling the air supply based upon changes in such distance. The devices for monitoring the patient distance include a heterodyning proximity detector, a force responsive distance sensing device, and a light responsive sensing device. The disclosure of U.S. Pat. No. 6,560,804 is incorporated herein in its entirety by reference.
Various other efforts have been made in the field to maintain the inflation of an air inflatable mattress at a particular height in order to maintain patient comfort.